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  Structural health management architecture using sensor technologyUSPTO Application #: 20060004499Title: Structural health management architecture using sensor technology Abstract: A mobile platform comprising at least one mobile platform system that includes a processor, a structure, and an SHM system. The SHM system also includes a processor as well as a structural sensor. The SHM processor is separate from the mobile platform system processor. In other preferred embodiments, the mobile platform includes a flight control system, a maintenance information system, and an IVHM system. The SHM system may receive parameters from the flight control system and calculate loads therefrom. Alternatively, the sensor may be a structural load sensor, which the SHM processor uses along with the parameters, to calculate other structural loads. In still another preferred embodiment, a method is provided that includes separating SHM functions from a processor of a mobile platform system. The method also includes dedicating an SHM system to perform SHM functions and establishing communications between the SHM system and the mobile platform system. (end of abstract) Agent: Robert Villhard Thompson Coburn LLP - St. Louis, MO, US Inventors: Angela Trego, Eric D. Haugse, Robert L. Avery, Aydin Akdeniz, Cori Greenberg, David M. Anderson, Richard J. Reuter USPTO Applicaton #: 20060004499 - Class: 701029000 (USPTO) Related Patent Categories: Data Processing: Vehicles, Navigation, And Relative Location, Vehicle Control, Guidance, Operation, Or Indication, Vehicle Diagnosis Or Maintenance Indication The Patent Description & Claims data below is from USPTO Patent Application 20060004499. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] This invention relates generally to structural health management and, more particularly, to systems, architectures, and methods for managing the structural health of mobile platforms such as aircraft. BACKGROUND OF THE INVENTION [0002] Maintenance costs have become a key component of the life cycle costs associated with commercial and military aircraft. Further, most of the expense of maintaining a metallic aluminum aircraft is associated with corrosion prevention and control. For a typical fleet of aircraft, 70% of all structural maintenance expense is incurred inspecting the airframes during periodic (frequency-based) maintenance tasks. More particularly, the majority of the inspection expenses are associated with accessing hidden portions of the airframe. The remaining 30% of the maintenance expenses are incurred actually repairing fatigue cracks and other structural damage found during the inspections. To put these expenses in perspective, more than twice the amount spent fixing damage is spent accessing the area, and performing the inspections for finding the damage. Thus, overall maintenance costs can be reduced by replacing periodic (frequency-based) inspections with a combination of automated detection of structural damage, degradation, (and the occurrence of events that might cause the same), and maintenance based on these conditions (i.e. condition based maintenance). [0003] The use of increasing amounts of non-traditional materials (e.g. composites) is changing the types of maintenance information desired for monitoring the health of the overall structure. For instance, less information regarding metallic corrosion will be desired while other additional types of information will be desired to ascertain the health of the composite members. Thus, the changes in the mix of desired information necessitate modifying the integrated vehicle health management (IVHM) system by adding various sensors, in particular, for monitoring the composites. These additional sensors include, but are not limited to, high bandwidth structural sensors, corrosion sensors, load, and inertial sensors. [0004] IVHM systems allow mobile platform operators to gather, record, and analyze information describing the operational status of the active components (including electronic components that are functionally active in that they produce observable outputs--signals) of their mobile platforms. For instance, modern turbojets are instrumented with sensors to monitor the engine and to detect incipient failures thereof. Upon detection of an incipient failure, the operator can correct the incipient failure in time to avoid schedule interruptions. Before the advent of IVHM, however, the operator would have periodically removed the engine from service for extensive inspections and preventative maintenance even in the absence of a condition warranting engine removal. Whether the inspections revealed damage or degradation of the structure, the frequency-based inspection approach requires the operator to incur costs by inspecting the engine. Also, the frequency-based inspection approach forces the operator to incur opportunity costs by removing the engine from service. After implementing IVHM on the engine, though, the operator now typically waits until the IVHM system detects a condition warranting engine removal prior to removing the engine from service. [0005] One area that IVHM systems do not address is the health of the passive structural members of the mobile platforms. The reasons that IVHM systems have failed to address structural health monitoring (SHM) include the difficulty of handling the large amounts of data and related processing that SHM entails. IVHM sensors are typically sampled at comparatively low frequencies (i.e. tens to hundreds of hertz or lower), whereas SHM sensors often require rapid sampling rates (i.e. hundreds to thousands of hertz or higher) to yield useful information. Further, an IVHM system typically monitors several hundred, to perhaps a thousand sensors, whereas an effective SHM system might have tens of thousands of structural members within its purview. Given the number of structural members and the high data rates associated with structural sensors, a completely instrumented, conventional, SHM system would overwhelm the throughput provided by today's flight-qualified processors and networks. Moreover, as with any mobile platform system, IVHM systems are constrained by the desire to conserve cost, weight, power, and space. Thus, increasing the size of the IVHM is not desirable. [0006] Therefore, a need exists to provide a practical SHM system for mobile platforms. SUMMARY OF THE INVENTION [0007] It is in view of the above problems that the present invention was developed. The invention provides improved SHM systems, architectures, networks, and methods. [0008] To address the need for structural health monitoring, the present invention provides autonomous SHM systems, architectures, networks, and methods, thereby enabling condition-based maintenance of the aircraft structure. Thus, the present invention assists maintenance personnel in their efforts to identify structural degradation and damage. Also, the present invention decreases the amount of frequency-based maintenance required for mobile platform structures. [0009] In a first preferred embodiment, the present invention provides a mobile platform comprising at least one mobile platform system that includes a processor. The mobile platform also includes a structure and an SHM system. The SHM system includes another processor and a structural sensor. The dedicated SHM processor is separate from the mobile platform system processor. In another specific embodiment, the SHM system may also process existing mobile platform parameters to determine structural loading conditions. In particular, the airplane parameters may be correlated with mobile platform loads via structural load models so that, depending on which loads are of interest, insight into the loads can be gained without the addition of structural sensors. In other preferred embodiments, the mobile platform includes flight control, maintenance information, and IVHM systems. In embodiments with a flight control system, the SHM system may receive parameters from the flight control system to determine loads on the structure therefrom. Alternatively, the sensor may be a structural load sensor, which the SHM processor uses, along with the parameters, to determine still other loads. In yet another preferred embodiment, the present invention provides a method that includes separating SHM functions from a pre-existing processor of a mobile platform system. The method also includes dedicating an SHM system to perform SHM functions and establishing communications between the SHM system and the mobile platform system. [0010] In a preferred embodiment the SHM system will monitor multiple areas of the aircraft structure to minimize maintenance by reducing or eliminating routine inspections and by assisting in the evaluation and assessment of non-destructive inspection for incidental damage or specific mandated inspections by regulatory agencies. Ideally a low-cost low weight system will allow 100% monitoring for all types of damage. However, initially high SHM systems costs (sensors costs, SHM processor, software & network costs, SHM installation costs, and maintenance costs) will not be practical for implementation. Therefore, in a preferred embodiment, the SHM system will support monitoring in areas that have high return with low cost risk, such as areas that are difficult to access for inspection or have a high cost impact due to frequent inspections or other cost factors--such as areas near, on, under or behind, the aircraft lavatories and galleys, floor beams, door surrounds, pressure bulkheads, fuselage and wing hard landing inspection areas, vertical stabilizer attachment, pylon to wing attachment and strut, fuselage crown structure, fuselage structure under wing to body fairing, wing ribs, cockpit window sills, wing center section, fuselage structure above the wing center section and main landing gear bay, and fuselage structure in the bilge area. In the preferred embodiment the SHM system sensors in sparse (or dense) arrays can also be used to support annoyance maintenance, non-safety issues, such as for locating acoustic vibrations. Another preferred embodiment also includes provisions for adding additional monitoring equipment throughout the airplane's service life. [0011] Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0012] The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and together with the description, serve to explain the principles of the invention. In the drawings: [0013] FIG. 1 illustrates an aircraft constructed in accordance with a preferred embodiment of the present invention; [0014] FIG. 2 illustrates a data system architecture of the aircraft of FIG. 1; and [0015] FIG. 3 illustrates a structural health monitoring architecture of the aircraft of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0016] Referring to the accompanying drawings in which like reference numbers indicate like elements, FIG. 1 illustrates a plan view of a mobile platform constructed in accordance with the principals of the present invention. The exemplary mobile platform illustrated is a commercial transport aircraft 10 that generally includes active components and passive structural elements. Though, the mobile platform 10 could be any type of mobile platform such as an aircraft, a spacecraft, or ground or marine vehicles. An IVHM system on the aircraft 10 monitors the health of the active components, whereas a dedicated SHM system (to be described in more detail herein) monitors the health of the structural elements. The monitored structural elements include a fuselage 12, a pair of wings 14, a vertical stabilizer 16, and a pair of horizontal stabilizers 18. These major structural elements 12 to 18 further include many assemblies, sub-assemblies, and individual components that are well known in the art. Generally, the structural elements 12 to 18 remain stationary with respect to each other, although some relative motion is inherent between the elements, for example as evidenced by flexing of the wings. The structural elements serve to distribute constant loads (e.g. the weight of the aircraft 10), dynamic loads (e.g. the thrust from the engines), and transient loads (e.g. shocks, vibrations, and impact induced impulses). Traditionally, the structural elements 12 to 18 are formed from various metals, particularly aluminum. Increasingly, though, the elements 12 to 18 are formed from composite materials, which behave in a more complex manner than traditional materials when subjected to a load. That is, when a traditional material might exhibit a strain, or yield, a composite material might also, for example, delaminate. Because increased insight into the health of the structure decreases inspection costs, aircraft operators can reduce overall maintenance costs by maintaining, or increasing, the amount of monitoring of airframe structures 12 to 18 and the sub-assemblies thereof. [0017] As shown in FIG. 1, the aircraft 10 also includes many active components that impart energy to the aircraft 10, or move relative to the aircraft 10, or to perform a variety of other functions. Typical active components, or assemblies, include a pair of engines 20, ailerons 22, elevators 24, and nose and wing landing gear mechanisms 26 and 28 respectively. Traditionally, the comparatively lower data rates and numbers of sensors required to adequately monitor the active components 20 to 28 (and sub-assemblies thereof) have allowed the conventional data systems onboard the aircraft 10 to perform IVHM for the active portions of the aircraft 10. [0018] By contrast, the structural members 12 to 18 comprise thousands of individual members (e.g. load carrying body panels, trusses, stringers, ribs, and the like). While many SHM sensors (e.g. strain sensors) operate at the comparatively lower sampling rates akin to the IVHM sensors, many other SHM sensors operate at much higher frequencies. For instance, shock, vibration, and ultrasonic non-destructive inspection sensors must be sampled rapidly to provide adequate insight into the phenomenon that they are intended to monitor. In contrast, corrosion sensors may be sampled infrequently (e.g. every minute, weekly, or monthly) yet still provide adequate insight into the health of the structure when analyzed on a less frequent basis (e.g. annually). Taken as a group, therefore, the SHM sensors generate a large volume (i.e. high bandwidth) of data for which existing aircraft data systems cannot economically, or practically, be configured to accommodate. [0019] Currently, scheduled inspections of the aircraft 10 structures are driven primarily by a given element's susceptibility to environmental considerations, although fatigue and susceptibility to accidental damage also play roles in the frequency of inspection. The present invention provides systems, architectures, networks, and methods to reduce the requirement for these periodic inspections. Also, the present invention provides strategically placed sensors and an autonomous SHM system to detect events and conditions that warrant unscheduled inspections. More particularly, sensors are included at difficult to access locations to reduce the need to inspect these areas. Thus, the present invention eliminates the time and labor required to access and inspect these inaccessible areas. Also, the time and labor necessary to repair damage to the aircraft, incidental to the access effort, is likewise eliminated. Further, because many of these areas are typically sealed (or otherwise protected from the environment) at the factory, the superior factory protection seal is maintained until a condition warranting intrusion is sensed. Continue reading... Full patent description for Structural health management architecture using sensor technology Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Structural health management architecture using sensor technology patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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